Safety device for elevators



I. R. STROUD.

SAFETY DEVICE Eon ELEVATORS.

APPLICATION FILED OCT. 25, 1919. 1,336,170.

l. B. STHOUD.

SAFETY DEVICE FOR ELEVATORS.

APPLlcATIoN. FILED ocr. 25, 191.9.

M336, l '70. Patented Apr. 6, 1920 2 SHEETS-SHEET 2.

FIGS.

WITNESSES INVENTOR JOHN RYAN STROUD, OF SCENERY HILL, PENNSYLVANIA.

SAFETY :DEVICE FOR ELEVATORS.

Application filed ctober 25,

To all whom t may concern.'

Be it known that l, JOHN B. S'rnoUD, residing' Scenery l-lill, in the county of lVashington and State of Pennsylvania, a of the United States, have invented or discovered certain new and useful lmprovements in Safety Bevices for Elevators, of which improvement the following is Va specication.

My invention relates to improvements in safety stops for elevator cars. lt is not so limited, but it nds immediate application in the elevators or hoists used in mines,

and it will further be understood in reading the ensuing specication that itis applicable equally to elevators moving on an incline, as well as to those moving vertically.

T he accompanying drawings illustrate my invention. Figure l is a fragmentary view in side elevation of a car with my safety device applied to it. In this figure parts of the safety device are shown in cross section. Fig. ll is a view in cross section through the guideway, showing the car with its safety device in plan. Fior., HI is a vertical section through the car on the line indicated at 3*,3, Fig. II. And Fig. IV is a side elevation at right angles to the showing of Fig. Y

|The elevator car or cage shown diagrammatically is indicated at 1, and requires no particular description. On either side of this car or cage, extending longitudinally in the direction of cage travel and adjacent the cage, are posts 2. These are coperating parts, as will presently appear, for the safety device. They may also serve (and ordinarily such is the case) as guideways for the car. Mounted upon the car in suitable bearings is a pair of shafts 3, and each of these shafts carries at either end and rotatable upon it, a cam ll. These cams on the `range of rotation recede from and come into contact vwith the posts 2. They are arranged pair by pair on opposite sides of each post, and as they come to post-engaging position, each pair forms a clamp upon the post.

Suitably mounted upon the car are motor members, conveniently taking the form of expansion springs 5, one for each cam, and these springs operate as they expand, through suitable gearing, to swing the cams from inactive to post-engaging position. As shown in the drawings, this connection Speccation of Letters Patent.

Patented Apr. (i, 1920.

i919. serial No. 333,330.

consists in each case of a pivoted beam or bar 5, provided with an arc of a gear-wheel 7, which arc meshes with a pinion face S, formed integral with cam a. lt will be seen that the beam (3 with its pinion arc 7 is but a portion of a complete pinion, and indeed, as will i ily be understood, a complete pinion mignt be employed, if it were convenie t so to do.

Each shaft 3, at the point where the cams are mounted upon them, is cut away to form semi-circumferential slots 9, and the cam members d are provi-ded each with a pin 10 enter-inv` the slot. lt will thus be seen that each cam has a range of rotation upon the shaft of 180o (the exact amount is unimportant), and that the abutment of the pin against the end of the slot prevents rotation.

Each shaft 3 is further provided at a suitable point (conveniently midway of its length) with a pinion 11 F ig. lV) and each pinion 11 is engaged by a rack 12, and accordingly as rack 12 moves through its range of permissible motion from one eX- tremity to another, so the shafts 3 will be turned. The parts are so proportioned and arranged that as the racks assume the alternate eXtreme positions shown in full and in dotted lines respectively in Fig. III, the shafts stand either in the position shown in Fig. with the grooves 9 beneath, or in a position 1800 removed from that, with the grooves 9 uppermost.

eferring now to Fig. III, the suspension of car 1 by car-sustaining cable 13 will be apparent. lt is effected through the link 11i which engages the car through a compression spring 15. In case the car-sustaining cable breaks, the spring 15, expanding, causes the link to move relatively to the car from the position indicated in full lines Fig. lll, to the dotted-line position. lt will further be observed from Fig. III that the racks 12 are connected to link 14, the arrangement being such that, in the' event of parting of the cable, the expansion of spring i5, moving linlr 11i in the manner indicated, will drive the racks 12 from one limit of intended motion to the other, and in so doing effect a corresponding turning of the shafts 8. The extent of turning so effected has already been indicated.

It remains only to note that, comparing Figs. I and III, so long as the car is hung by the car-sustaining cable 13, the cams remain `in the position shown. In that position the tension of springs 5, exerted through the gear connection 7 and S, hold the cams l in the position shown, the pins 10 abutting against the ends of the slots 9. The shafts 3 are held immovable bythe weight of the car in fixed position respecting racks 12.

' This abutment of the pins 10 against the ends of slots 9 is effective to prevent expansion of springs 5, so long as thel car is sustained by its cable. It is apparent that it is the weight of the car, acting through these instrumentalitiea that holds both spring 15 and springs 5 lcompressed and under tension. In case the car-sustaining cable, parts, immediately these things Vhappen: link 14 moves downwardly, ,carrying racks 12 5 shafts 3 are rotated until grooves 9 are uppermost; springs 5 are then free to expand.V ln expanding they swing beams 6 and, through the gearing 7, 8, cause cams t to turn until the carin faces come into bearing upon posts 2 and, inasmuch as there are two of these clamping members acting as al pair on opposite sides of each post, a clamping such as to arrest the falling of the car is effected. Y.

, It remains to note certain characteristics of thissafety device. First of all, it is to be observed that each cam is driven independently 'of the others. In the form shown each has its own motor, namely, an expansion spring 5. lVhen once the shafts 3 have turned under the conditions and in the manner explained, each cam, separately driven, is free to move'through its whole range of motion, or so much thereof as is requisite to bringing its acting face in contact with the post. 'This is a feature of great advantage; for, where such post-engaging cams are mounted so that they are'mechanically coupled together to act in pairs or in sets, there is no provision made to overcome defective engagement of a post, in case the car happens to occupy an asymmetrical position. It is not uncommon for a car to become slightly twisted in its runway, and then one of a pair of post-engaging 'cams may be very much nearer the face of its post than the other, and where there are four cams, two may be quite near to and two quite remote from post engagement. Furthermore, these posts wear away, and are apt tohave irregularities of surface, so that there are accidental variations of distance between cam and post. Vhen cams are harnessed to actin pairsorfin sets of four, the safety device may be ineffective or "faultily effective, by reason lof the fact that some' only of the cams take purchase upon the lface ofthe post. .ut b'y my invention, in lwhich each cam 'is unrestrained by any other and is free to move under its impelling force until it makes contactV with the' face of the post, a sure engagement is provided for. t

Another feature of advantage is this. Having, as l show, and as 1 preferably employ, a separate expansion spring for each cam, 1 may make those springs as heavy asl will, and l may thus insureknot merely force enough to bring the cam into ing, in combination with a travelingY car hung bya cable, a post entendingadjacent the car and in the directionof car travel, two shafts borne by said carandrotatable in suitable bearings, means operated on the parting of the car-sustaining cable for turning said shafts, a pair of post-engaging cams borne one by each of said shafts and capable of limited rotation thereon, 4and means for rotating each cam upon its shaft independently of the other, substantially as described. Y

2. A safetydevice forelevators including, in VcombinationV with a traveling car hung by akcable, a post extending adjacent the car and in .thev direction of car travel, two `shafts borne by the car and rotatable in suitable bearings, means operated on the parting of the cable for rotating Vsaid shafts, a pair of post-engaging cams Vborne one by each of said shafts androtatable thereon within predetermined limits, a pair of tension springs, and two sets of gearing operated severally by said springsand operating severally said cams, substantially as described.`

3. A' safety device for elevators includling,V in combination with a traveling car hung by a cable, a post extending adjacent the car and in the direction of car travel, two shafts'borne by the carl and rotatable in suitable bearings, a pinion keyed to each of said Vshafts,; a rack engaging each of said pinions, means for` shifting said racks on they parting ofthe car-sustaininglcable, a pair of post-engaging cams borne. one rby each of' said'shafts and capable oflimited rotation thereon, and means for. rotating each cam uponrits shaft .independently of the other, substantially as described.l

il. A safety Vdevice for elevatorsincluding, in combination with a car` sustained by a cable, a post extending adjacent the path of car travel, two intermeshing pinion niembers borne by saidl car, a motor member constantly exerting a turning tendency upon one of said pinion members, a movable postengaging cam borne to post-engaging position through the turning of the other of said pinion members, a member movable to and from engagement With the second of said pinion members, held to such engagement by the Weight oi the car when sustained by its cable, and When se held overcoming the tendency of said motor member to turn said pinion members and bring said cam to ost-enffaoino` osition and means D b D 7 effective on the parting of the car-sustaining cable for moving the member last named from the engagement defined, substantially as described. Y

5. A safety device for elevators including, in combination With a car sustained by a cable and a post extending adjacent the path of car travel, a shaft rotatable in its mountings in said car and having a slot in its surface partl 1 encircling it, a pinion With a cam face rotatable upon said shaft and provided with a pin entering said slot, and means for bringing the said shaft to one or the other of two alternate positions of rotation accordingly as the car is sustained by its cable or released, and means tending constantly to rotate the cam upon said shaft, substantially as described.

6. A safety device for elevators including, in combination with a car sustained by a cable, a pest extending adjacent the path of car travel, tivo pairs of intermeshing pinion members borne Aby said car, a motor member constantly exerting a turning tendency upon one of the pinion members of each pair, a pair of movable postengaging cams borne to post-engaging position through the turning o1 the other menibers of the pair of pinions, and members movable to and from engagement With the second-mentioned pinions of the pair, held to such engagement by the Weight of the car When sustained by its cable, and when so held overcoming the ytendency of said motor members to turn said pinion members and bring said cams to post-engaging position, substantially as described.

ln testimony WhereoiC l have hereunto set my hand.

JOHN RYAN STR-OUD.

lVitnesses:

BAYARD H. CHRISTY, FRANCIS J. ToMAssoN. 

